Factors affecting mechanical properties of aluminum alloy ingot as cast

The main factors affecting the mechanical properties of cast ingot are grain size, intrachrystalline structure, ingot density, microstructure heterogeneity, chemical composition and regional segregation. Generally, under the condition of a certain chemical composition, the smaller the grain size, the finer the intrachrystalline structure, the higher the density, the smaller the degree of microstructure heterogeneity and the lighter the degree of regional segregation, the higher the comprehensive mechanical properties of the ingot. Among them, for industrial pure aluminum and soft alloys, the determining role is the grain size; For high component hard alloys, the fineness and density of the intrachrystalline structure play a decisive role.

The distribution of mechanical properties along the ingot section varies with different casting conditions. Water cooled semi-continuous casting. At the ingot edge, the lower mechanical properties are due to the lower thermal conductivity of the mold wall. At the outlet of the mold, the strength of the ingot increases sharply, which increases the crystallization speed and results in improved mechanical properties. The performance in the ingot base area decreases sharply as a result of the reduced speed and the expanded size of the transition zone.

When the casting speed is low, the distribution of properties along the section is more uniform. Increase the casting speed, so that the performance of the above distribution law more obvious. It is easier to obtain more uniform properties when the casting speed is increased by using high crystallizer than by using low crystallizer, but the average mechanical properties of ingot are decreased.